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Date:   Thu, 4 Oct 2018 14:06:37 +0530
From:   Viresh Kumar <viresh.kumar@linaro.org>
To:     Rob Herring <robh@kernel.org>
Cc:     Rajendra Nayak <rnayak@codeaurora.org>,
        Stephen Boyd <sboyd@kernel.org>,
        Andy Gross <andy.gross@linaro.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        David Collins <collinsd@codeaurora.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        devicetree@vger.kernel.org,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 2/6] dt-bindings: power: Add qcom rpm power domain
 driver bindings
Message-ID: <20181004083637.xlz26rpn4qtsvdk7@vireshk-i7>
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On 25-09-18, 14:43, Rob Herring wrote:
> On Tue, Sep 25, 2018 at 5:25 AM Rajendra Nayak <rnayak@codeaurora.org> wrote:
> >
> > Hi Rob,
> >
> > []...
> > >>>>> +   rpmhpd_opp_table: opp-table {
> > >>>>> +           compatible = "operating-points-v2-qcom-level";
> > >>>>> +
> > >>>>> +           rpmhpd_opp_ret: opp1 {
> > >>>>> +                   qcom,level = <RPMH_REGULATOR_LEVEL_RETENTION>;
> > >>>>> +           };
> > >>>>
> > >>>> I don't see the point in using the OPP binding here when you aren't
> > >>>> using *any* of the properties from it.
> > >>>
> > >>> Yeah, that's the case for now. But there are cases (as Stephen
> > >>> mentioned earlier [1]) where the voltage values (and maybe other
> > >>> values like current, etc) would be known and filled in DT. And that's
> > >>> why we all agreed to use OPP tables for PM domains as well, as these
> > >>> are really "operating performance points" of these PM domains.
> > >>
> > >> Rob, are you fine with these bindings then?
> > >
> > > Okay, my only thought is whether we should just use 'reg' here, or do
> > > we need 'level' for anything else and should make it common?
> >
> > I am not quite sure I understood what you are suggesting here :(
> 
> You could use the  'reg' property instead of 'qcom,level'. Any reason
> not to do that?

They can use any property which uniquely identifies the OPP nodes in
the table. Though I never thought we can use 'reg' property in such a
way. I always thought it must be related to registers somehow :)

Yeah, CPU is one of the examples where 'reg' has a special meaning.

> Alternatively, would 'level' be something useful in other situations
> and should not be QCom specific?

It is too early to say that. The only platform which needs this is
Qcom right now, lets see what the requirements from other users are.

-- 
viresh